3. A stack is a data structure which is used to store data in a particular order. (a) One of the applications that apply stack concept is to compute arithmetic expression. Evaluate the following postfix notation of expression: 5, 20, 15, -, 25, 2, *, + Show the status of stack after execution of each operation. (10 marks) (b) Given the following structure of bookInfo definition containing book information to be implemented using a stack: struct book Info { int BNO ; char BName (20) ; struct bookInfo *next ; Write C++ statements to perform the task below: i. To insert a new node into the stack. Assume that the new node is already created and pointed by a pointer called newNode. (4 marks) To delete a node containing book information from the stack. (6 marks)